Reaction products of thiuram disulfides and alkylene imines



rriatter andm'ore specifically it mill; or in aninternal mixer, or

Suitable usedalong with similar dioeii in 'an'ainino gro l.

Patented Feb. 1, 1949 FEBES AND 'ALKYLENE IMINES il'acob iii-den Hansen, kin-on, Ohio,

assignor to The B. F. Goodrich Company, New York, N. Y-.,ia

corporationoi' New York Ne D ra'vviil'g. "l ipplicationfipril 30, ISM-'5, Serial No. 591L223 Claims. (oi. zoo-239) This inventionrel'a'tes to new'c'ompositions'of relates to the products of the reaction of an alkylene 'imine with a tliiuram diSulfid'e- These products whose structures are not definitely known are useful'asaccelerators and activators of vulcanization ofdruhher. Among the rubbers which may be-vulc-anized with the 'help or t see new compound-sari:.allvarieties of natural rubber such "as caout'chouc; b'al'ata, gutta percli'a, latex, reclaimed rubber, artificial rubber isomers-and such s'y'rithetic rubbers as 'can be vulcani'aed with sulfur such as polymers cf butadiene, isoprene; 2;3:dimetny1 butad-iene, piperyl- 'eiie-"and'thelik'e, and'copolymers ofthese compounds with aLcrylohitfil-e,styrene, methyl acrylate,metliyl 'i'nethacrylate, isobiitylene and other *copolyfneri'zable moiiom'ers.

Thesenew compounds may be added =to' the rubber on 'a roll by any other method. Other compounding ingredients si1'chas any of the ord-in'ary'pi'gments, fillers, eyes. antioxidantsor other accelerators of vulcanization maybsempmysd withzn'iy new-materia-ls. Small quantities may be use d to achieve the desired results, either as vulcanization ac-tivators or accelerators-. ln genera'l', 0. 1 to 5% or more, based'onth'e runner composition, may be proportion of sulfur or a sulfur donor, 'oreveninore if a'hard' vulcanized rubbe sto bema'de'. v

*LX CCOl ring to theiireferred proedure of my invention; thesereaction products are -paepa'red nyreact e twc 'inolcularportion or an amylene imine with one molecular portion of a tliiuram iii-sulfide having-at "least one active hyin'the presence oi any of the commonly used eacti'on. diluents such as water", 'h-ehzndalcia'hol and. the like. The reaction will take place in. the absence of a diluent, but the reaction rate is then so fast that it is difiicult to control. Therefore, for optimum cp= crating conditions, a reactiondiluentis desirable. It has been found that the reaction will progress even at roomtemperature, and the heat of reaction will be removed sufilciently by a cold 'water "oath tornaintain a reaction temperature below Alkylene 'iinineswill react with these thiur-ain disulfides in other proportions than that given above. If desired, the ratio can he changed to 'eduiiziolecular portions; or-th'eal-kylene imi-ne can be increased above the two-no-one ratio. It Will be understood that varying the imine to disulfide ratio will produce products having properties in 50 ml. of methanol; slowly to the disulfide suspension with stirring 7 unsubstituted thiuram disulfide are 2 generally the same as those of the preferred product describedabove.

The following specifie' examples will serve'more fully to-illustrate my'invention. Example I 18.4 grams of unsubstituted thiuram disulfide (0.1 gram molecular equivalents) are suspended in 156 ml. of methanol in a three-neck flask fitted with an agitator,- a; thermometer and "a dropping funnel. 8:6- gramsof; ethylene imine (-03 gram,molecular equivalent-s) are dissolved This solution is added While thereaction. flask remains immersed; in a cold. water bath to maintain a, reaction temperature not greater than 35 C. The imine solution fi'sadded over a oeriodoi '25 minutes. sometof the disulfid'e is 'still in suspension. agra ms excess of 'imine isadd'edand the reaction mixture is allowed test-ended minutes during which time the reaction medium (clears and an oily material settlesout'. The oily product is separated from the reaction medium by evaporating the methanol at reduced pressureat 25? C. and'the resulting thick, clear, yellow pouralole oil-weighs '265 grains having a refractive index at 25 C. of 1.6625.

Example II 18.4 grams (0.1 gram molecular equivalents) Of suspended in m1. of methanol in a reaction flask fitted with a stirrer, a thermometer and a dropping funnel, and placed in a water bath ior cooling. 17.2 grams (0.4 gram molecular equivalents) of ethylene 'imine are addednropwise over a period of 20 minutes while maintaining a reaction tern peratureof not over 35 C. Thewater bath-is removed and stirring continued over a period 'of is minutes after whieh'the methanol is removed under reduced' pressure' at-25"to '30 C. The resulting reaction p'roduct is a: viscous, "clear, dark oilwelghing '35 grams-having an index of refraction of 1.6275 at 25 C.

17.4 grams of dicyclohexi l thiuram disulfi'de (3.05 gram molecular equivalents) are suspended 1'50- ihi; for rnethanol as Example 11. 4:3 gramspfethylene infiine are added over .a-perio-d 'of5 rhinut'es withno' "temperature change in the reaction mixture. After stirring for 20 minutes longer, the temperature rose from 27 C. to 33 C. and remained at 32 to 33 C. for 20 minutes and then falls slowly and comp1ete solution is effected. The mixture is stirred two hours longer. The very viscous reaction product which contains some solid material is separated from the methanol by removing the methanol under reduced pressure at 25 C. The reaction product weighs 21 grams.

Other three-membered ring alkylene imines that can be substituted for ethylene imine in the above examples without departing from the scope of my invention are the homologous hydrocarbon-substituted ethylene imines, such as propylene imine and the like.

Similar reaction products may be obtained by replacing the unsubstituted thiuram disulfide in the above examples with any thiuram disulfide having at least one active hydrogen atom in an amino group derived from dithiocarbamates of.

primary amines, such as dimethyl thiuram disulfide, trimethyl thiuram disulfide, dimethyl ethyl thiuram disulfide, triphenyl thiuram disulfide, diphenyl tolyl thiuram disulfide and other alkylor aryl-substituted thiuram disulfides. These reaction products will be produced with results equal to that in the above examples.

The products of the reaction between alkylene imines and thiuram disulfides are all good vulcanization accelerators. As an indication of the ability of these compounds to accelerate the vulcanization of rubber, the following example illustrates the efiect produced in rubber by the product of the reaction between unsubstituted thiuram disulfide and ethylene imine. A typical high gum stock of the following composition, in which the parts are by weight, was prepared:

. Parts Natural rubber 100.0

Zinc oxide 5.0

Sulfur 3.0

Stearic acid 1.0 Thiuram disulfide ethylene imine reaction product 1.0

After vulcanization in a press at 287 F., the composition had the physical properties as shown in v the following table, in which T is the ultimate tensile strength in 1b./sq. in. and E is the ultimate elongation in percent.

Time of vulcanization in minutes T E materials utilized may be varied and other materials having equivalent chemical properties may be employed, if desired, without departing from 4 the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A viscous oily reaction product, useful as an accelerator and activator for the vulcanization of rubber, prepared by bringing together, in an inert liquid diluent, reactants consisting of one molecular proportion of a thiuram disulfide having at least one hydrogen atom in an amino group, and two to four molecular proportions of an alkylene imine, maintaining the reactants at a temperature between room temperature and about 35 C. until heat of reaction is no longer evolved, and then removing the inert diluent.

2. A viscous oily reaction product, useful as an accelerator and activator for the vulcanization of rubber, prepared by suspending, in an inert liquid diluent, one molecular proportion of a thiuram disulfide having at least one hydrogen atom in an amino group, adding t the resulting suspension two to four molecular proportions of ethylene imine, maintaining the resulting mixture at a temperature between room temperature and about 35 C., until heat of reaction is no longer evolved, and the removing the inert diluent.

3. A viscous, yellow, pourable oil, having a. refractive index at 25 C. of 1.6625 and being useful as an accelerator and activator for the vulcanization of rubber, prepared by suspending in an inert liquid diluentone molecular portion of unsubstituted thiuram disulfide, adding to the resulting suspension two molecular proportions of ethylene imine, maintaining the resulting mixture at a temperature between room temperature and about 35 C., until heat of reaction is no longer evolved, and'then removing the inert diluent.

4. A viscous, clear, dark oil, having a refractive index at 25 C. of 1.6275 and being useful as an accelerator and activator for the vulcanization of rubber, prepared by suspending in an inert liquid diluent one molecular portion of unsubstituted thiuram disulfide, adding to the resulting suspension four molecular portions of ethylene imine,

maintaining the resulting mixture at a temperature between room temperature and about 35 C., until heat of reaction is' no longer evolved, and then removing the inert diluent.

5. A viscous oily reaction product containing a minor portion of solid material and being useful as an accelerator and activator for the vulcanization of rubber, prepared by suspending in an inert liquid diluent one molecular portion of dicyclohexyl thiuram disulfide, adding to the resulting suspension two molecular proportions of ethylene imine, maintaining the resulting mixture at a temperature between room temperature and about 35 C., until heat of reaction is no longer evolved,

and then removing the inert diluent.

JACOB EDEN JANSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,551,042 Miller Aug. 25, 1925 1,613,573 Bedford Jan. 4, 1927 2,214,460 Harman Sept. 10, 1940 OTHER REFERENCES Chemical Abstracts, vol. 35, page 6148 (1941). 

